gpiolib: Don't return -EPROBE_DEFER to sysfs, or for invalid gpios

gpios requested with invalid numbers, or gpios requested from userspace via sysfs should not try to be deferred on failure.

---
 drivers/gpio/gpiolib.c |   10 +++++++---
 1 files changed, 7 insertions(+), 3 deletions(-)

index 141f793..b59d240 100644
@@ -651,9 +651,11 @@ static ssize_t export_store(struct class *class,
 	 */
 
 	status = gpio_request(gpio, "sysfs");
-	if (status < 0)
+	if (status < 0) {
+		if (status == -EPROBE_DEFER)
+			status = -ENODEV;
 		goto done;
-
+	}
 	status = gpio_export(gpio, true);
 	if (status < 0)
 		gpio_free(gpio);

@@ -1220,8 +1222,10 @@ int gpio_request(unsigned gpio, const char *label)
 
 	spin_lock_irqsave(&gpio_lock, flags);
 
-	if (!gpio_is_valid(gpio))
+	if (!gpio_is_valid(gpio)) {
+		status = -EINVAL;
 		goto done;
+	}
 	desc = &gpio_desc[gpio];
 	chip = desc->chip;
 	if (chip == NULL)

1.7.4.1

Very good catch. I applied this to my fixes branch and also put the stable tag on this thing, it goes way back to the introduction of deffered probe.

Mark: OK with this?

Yours,
Linus Walleij

The invalid numbers thing I'm a bit meh on. It came up before and I personally wasn't sure if the issue wasn't with gpio_is_valid() only checking for "this number could possibly ever be a GPIO" and not doing any checking against the GPIOs that have actually been registered. If it's the former then ideally at some point in the future we'll remove the big table and gpio_is_valid() will always be true.